Abstract: Attenuation experiments are introduced with the emphasis on a YAG pulse laser system with wave length of 1 06μm.The experiments include two parts:first,the measurement of laser signal attenuation through the flames above the burning propellant strands in a strand burner in order to compare the relative attenuation characteristics of different propellants;second,the measurement of laser signal attenuation through exhaust plume of a scaling down single chamber dual thrust solid propellant rocket motor in its sustain period.The experiments demonstrate that an obvious difference in the relative attenuation(from 2.6% to 12.7%)exist among the various propellants(DB,PS,HTPB and CMDB propellant)at same measuring conditions;the Al content in propellant formulation is a major factor of the attenuation;and the attenuation of the scaling down motor plume(35.7%)is more severe than at of the propellant strand flame because of the longer path and the higher concentration of particles in the plume.